All Small Six 61 falcon 200l6. Full overhaul. Keeps leaking coolant external on dr side

[Gml motorsports]

I’m at my wits end with this one boys,I have been an engine builder and machinist for ten years
Never had this issue before. I built an engine for a customer of mine it runs great awesome response28 miles to the gallon ! he was happy until it started leaking coolant on the driver side of the block between the head and block . The block was bored .040 decked and the head was gone thru completely all new parts. he probably had 50 mi on it when we noticed the leak so we replaced the head gasket With felpro 7916pt1. Head and block were true still leaked 20 mi later , replaced bolts with studs cut down front passenger stud that contacts water pump and used thread sealer chased bolt holes used appropriate arp lube on fastener still leaks. Took off head Magna flux block and head pressure tested block and head. No crack at all put back together with the studs. And the high track sealer on head and block still leaks. I am so over the project I wish he would of bit on the 302 swap

 

[Engine Fan]

Try GM coolant tabs

 

[Gml motorsports]

I used blue devil this last time still didn’t seal

 

[drag-200stang]

Usually head and block deck will fix that, I hear good things about Hylomar spray. Is it possible that the radiator cap is not relieving excessive pressure?
One good thing about the 200 it won't split in half if you boost the crap out of it and the intake will never leak.

 

[drag-200stang]

The Fel-pro PT gasket is the best off shelf gasket for boost but for sealing water, oil, I think that because the silicone does not go in a complete circle may cause leaks and a regular composite gasket may seal better.

 

[powerband]

... before adding another favorite assembly method / adjunct, can you be 101% sure it;s not an oil trail from the VC ?. I've had similar issues
.
With fresh milled true surfaces a standard composite gasket with or without sealant should not be the problem. Keep it s... .
.
my $ .02:
Copper spray sealant light coat , ARP fasteners - torque to your specs'.


hav e fun


.
useless anecdotes:
the '63 wagon has a Maverick 170 with a D7xx head worked and milled to 48cc chambers. Uses a "steel shim" extra thin non-composite gasket (@.015 - .020) - copper spray - for @ 9.5:1 SCR. Good mileage and performance with 91+ octane . No cyl/block leaks over 10 years
.
'74 Maverick 250 has the FelPro / copper spray and no leaks with 5-10 lbs boost. ( had machinist check D2xx head for true but NOT milled for SCR @ 8:1 with typical thick (.045-.050" ?) Composite and OEM @62cc chambers... )
.


.

 

[Gml motorsports]

Good radiator cap brand new rad as well dosent overheat. And I am shure its coolant I used up die because I thoug it may be coming from the thermostat housing. And update. I let the coustomer keep driving it with the blue devil and it blew the gasket between 5/6 and runs like crap now

 

[flatford6]

I had the same kind on leaks from the center drivers side of the head gasket on 200 inch motors used for driving 700 gpm water pumps for spraying construction sites. The more serious water leaks were from the same triangular water transfer ports into the push rod holes and into the oil pan. Check for water in the oil. The cure is to carefully punch out the triangular gasket holes with a 7/8 inch gasket punch. Save the pieces punched out and use a grinder to reduce the outside diameter of the punched out pieces to 3/4 inch. Use sand paper to smooth the 7/8 holes in the gasket. This will minimize damage to the 1/16 inch thickness high temperature O ring 7/8 od x 3/4 id. Put the head back on the engine with the oring in the head and the 3/4 inch round piece with the triangular hole inside the to keep the same water circulation arrangement. MAKE SURE you use a .040 thick gasket!!! This will give a .020 inch crush on the oring. Use silicon sealer if you are in secure. Do the 3 middle water transfer ports this way. If the engine is still together, go for as fast a ride as possible with the two middle spark plug wires grounded. The leak will stop because the leak is very sensitive to power level and heat levels. I did this many times when we did not want the truck down when we had jobs for it to do. The 200 had sufficient power to run the pump on only 4 cylinders.

 

[flatford6]

Continuing, water in the oil will evaporate when the oil get hot and the vapor will be sucked through the pcv valve and inpair idle quality. This was the first indication of the leaks. Incidently these heads will crack in the center on top between the center valve springs especially the later heads.

 

[levi0464]

I had this same issue with my '64 170 bored 0.030 over. This is a fairly common issue with these engines. Apparently some kind of sealant such as permatex copper spray or high tack applied to both sides of the head gasket is necessary to avoid this issue. I replaced the felpro 7916 pt1 with a steel shim head gasket using copper spray on both sides and haven't had any issues since.

 

[Gml motorsports]

I had the same kind on leaks from the center drivers side of the head gasket on 200 inch motors used for driving 700 gpm water pumps for spraying construction sites. The more serious water leaks were from the same triangular water transfer ports into the push rod holes and into the oil pan. Check for water in the oil. The cure is to carefully punch out the triangular gasket holes with a 7/8 inch gasket punch. Save the pieces punched out and use a grinder to reduce the outside diameter of the punched out pieces to 3/4 inch. Use sand paper to smooth the 7/8 holes in the gasket. This will minimize damage to the 1/16 inch thickness high temperature O ring 7/8 od x 3/4 id. Put the head back on the engine with the oring in the head and the 3/4 inch round piece with the triangular hole inside the to keep the same water circulation arrangement. MAKE SURE you use a .040 thick gasket!!! This will give a .020 inch crush on the oring. Use silicon sealer if you are in secure. Do the 3 middle water transfer ports this way. If the engine is still together, go for as fast a ride as possible with the two middle spark plug wires grounded. The leak will stop because the leak is very sensitive to power level and heat levels. I did this many times when we did not want the truck down when we had jobs for it to do. The 200 had sufficient power to run the pump on only 4 cylinders.

I am not understanding like put a viton o ring in between the head and block

 

[flatford6]

Exactly. The o ring keeps the water from flowing out of the triangular transfer ports to the outside or inside into the engine oil.

 

[chad]

80Lb tq to head studs? Or whatever is
Slightly over specs to stop (w/re-check on short break in)?

What is checked compression - way hi?
Put on coolant pressure checker to see how fast/where leeks?
Over heated @ break in? Timing OK right now?

I’ll not ask/talk abt motor assembly as it sounds ur experienced but follow specific i6 regime closely...
I’ve never needed any of the above helpful additions & I cant see Y this 1 needs them so will cont to watch
ur progress. Keep talkin~

 

[Gml motorsports]

Timing 30 overall locked out
Head studs torqued to 80 lbs with appropriate sealant for wp hole and Molly for threads and bottom of nuts
Compression ratio is 9.2:1
Never overheated manually checked with ir and guage

 

[chad]

ok, that last one wuz due to seein a guy’s break-in vid here
and the pipes glowed cherry red. Later (300 - 500 mi?) he
had troubles diagnosing ‘issues”. Think these other things
(listed above) can help? Willing to try? I’d like to know~
Sorry abt it, frustrating ! Good Luck, keep talkin...